General secretary Frances O'Grady said: "Millions of working people enjoyed paid holidays in their job for the first time thanks to the rights we won from Europe, and millions more got extra time off to spend with their children and their friends, go away with the family or simply have a well-earned break.

"Decent amounts of holiday pay for all is a relatively recent win, fought for by generations of trade unionists, and guaranteed by the EU. We can't take it for granted.

"But voting to leave the EU risks the paid holidays of millions.

"We know that some of the biggest cheerleaders for Brexit see protections for ordinary British workers - like paid holiday - as just red tape to be binned.

"And we know that bad bosses are rubbing their hands with glee at the prospect of being able to cut workers' hard-won entitlements.

"The risk to paid holidays just shows that voting to leave the EU is a step into the unknown for everyone who works for a living."